Released hostmanager 3.1
Merge pull request #298 from dswd/hostmanager-3.1

Released hostmanager 3.1
Fixed server stopping and fixed a bug in link measurements
Added repeated host error mails
Merge pull request #300 from dswd/repeated-error-mails

Added repeated host error mails
added description for external networks
fixed an error
added descriptions to organization, site and host in backend
Merge branch 'master' of https://github.com/GLab/ToMaTo into more_descriptions
migration for descriptions
added new field to info and modify
added descriptions to hosts
added descriptions to sites
added descriptions to organizations
changed column orders
added site description to editor
creation date of a template is now shown in editor
changed "no nlXTP icon" to be a warning instead of an error
first version of nlXTP icon
Merge branch 'master' of https://github.com/GLab/ToMaTo into nlXTP_icon